dubbo.apache.org/dubbo-go/v3@v3.1.1/filter/generic/filter.go (about)

     1  /*
     2   * Licensed to the Apache Software Foundation (ASF) under one or more
     3   * contributor license agreements.  See the NOTICE file distributed with
     4   * this work for additional information regarding copyright ownership.
     5   * The ASF licenses this file to You under the Apache License, Version 2.0
     6   * (the "License"); you may not use this file except in compliance with
     7   * the License.  You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   */
    17  
    18  // Package generic provides generic invoke filter.
    19  package generic
    20  
    21  import (
    22  	"context"
    23  	"sync"
    24  )
    25  
    26  import (
    27  	hessian "github.com/apache/dubbo-go-hessian2"
    28  
    29  	"github.com/dubbogo/gost/log/logger"
    30  )
    31  
    32  import (
    33  	"dubbo.apache.org/dubbo-go/v3/common/constant"
    34  	"dubbo.apache.org/dubbo-go/v3/common/extension"
    35  	"dubbo.apache.org/dubbo-go/v3/filter"
    36  	"dubbo.apache.org/dubbo-go/v3/protocol"
    37  	invocation2 "dubbo.apache.org/dubbo-go/v3/protocol/invocation"
    38  )
    39  
    40  var (
    41  	genericOnce sync.Once
    42  	instance    *genericFilter
    43  )
    44  
    45  func init() {
    46  	extension.SetFilter(constant.GenericFilterKey, newGenericFilter)
    47  }
    48  
    49  // genericFilter ensures the structs are converted to maps, this filter is for consumer
    50  type genericFilter struct{}
    51  
    52  func newGenericFilter() filter.Filter {
    53  	if instance == nil {
    54  		genericOnce.Do(func() {
    55  			instance = &genericFilter{}
    56  		})
    57  	}
    58  	return instance
    59  }
    60  
    61  // Invoke turns the parameters to map for generic method
    62  func (f *genericFilter) Invoke(ctx context.Context, invoker protocol.Invoker, invocation protocol.Invocation) protocol.Result {
    63  	if isCallingToGenericService(invoker, invocation) {
    64  
    65  		mtdname := invocation.MethodName()
    66  		oldargs := invocation.Arguments()
    67  
    68  		types := make([]string, 0, len(oldargs))
    69  		args := make([]hessian.Object, 0, len(oldargs))
    70  
    71  		// get generic info from attachments of invocation, the default value is "true"
    72  		generic := invocation.GetAttachmentWithDefaultValue(constant.GenericKey, constant.GenericSerializationDefault)
    73  		// get generalizer according to value in the `generic`
    74  		g := getGeneralizer(generic)
    75  
    76  		for _, arg := range oldargs {
    77  			// use the default generalizer(MapGeneralizer)
    78  			typ, err := g.GetType(arg)
    79  			if err != nil {
    80  				logger.Errorf("failed to get type, %v", err)
    81  			}
    82  			obj, err := g.Generalize(arg)
    83  			if err != nil {
    84  				logger.Errorf("generalization failed, %v", err)
    85  				return invoker.Invoke(ctx, invocation)
    86  			}
    87  			types = append(types, typ)
    88  			args = append(args, obj)
    89  		}
    90  
    91  		// construct a new invocation for generic call
    92  		newargs := []interface{}{
    93  			mtdname,
    94  			types,
    95  			args,
    96  		}
    97  		newivc := invocation2.NewRPCInvocation(constant.Generic, newargs, invocation.Attachments())
    98  		newivc.SetReply(invocation.Reply())
    99  		newivc.Attachments()[constant.GenericKey] = invoker.GetURL().GetParam(constant.GenericKey, "")
   100  
   101  		return invoker.Invoke(ctx, newivc)
   102  	} else if isMakingAGenericCall(invoker, invocation) {
   103  		invocation.Attachments()[constant.GenericKey] = invoker.GetURL().GetParam(constant.GenericKey, "")
   104  	}
   105  	return invoker.Invoke(ctx, invocation)
   106  }
   107  
   108  // OnResponse dummy process, returns the result directly
   109  func (f *genericFilter) OnResponse(_ context.Context, result protocol.Result, _ protocol.Invoker,
   110  	_ protocol.Invocation) protocol.Result {
   111  	return result
   112  }